Ecosystem based approaches to climate adaptation – Urban prospects and conflicts

Urban areas are particularly prone of negative impacts of climate change. Dense and impermeable surfaces such as pavements, streets and squares, and densely built areas for housing, institutions and businesses contribute to i) increased temperatures in summer compared to the surrounding landscape (the so-called urban heat island); and ii) larger amounts of rainwater amass and are more quickly concentrated in the sewage system than in the surrounding area leading to increased risk of flooding on streets, plots and cellars. Urban areas represent a specific climate risk with regard to damagers on material goods, health and welfare due to the way in which urban areas are planned and built. The majority of the world population now lives in urban areas. In Europe, about 75% of people live in urban areas, a trend that’s expected to increase to 80% by 2020. The municipality of Copenhagen experience a net migration of an average 1,000 people per month.
Solutions to climate challenges in cities can partly be found by making use of Nature’s ability to absorb and control the impacts of climate change, e.g. through increased planting of the urban space, green roofs and (recreative) areas designed to handle temporary flood events. It is expected that the use of ’green infrastructure’ can be economically more efficient as well as socially and ecological just compared to a sole focus on technical ’grey’ infrastructures and solutions. Simultaneously, there is a strong competition for space in cities.
In this project, we investigated the possibilities and conflicts linked to systematically applying an ecosystem based approach to climate adaptation in the municipality of Copenhagen. For practical reasons, we chose to focus on the ecosystem service ’water regulation’ from green roofs. A number of other positive impacts of green roofs such as temperature regulation, aesthetics and protection of roof material were included to less extent.